Pocket sharpener for knives

ABSTRACT

A blade sharpening tool adapted for hand-held use, comprising two mating housing components and two bits wherein the bits can be of tungsten carbide material. Each mating housing component can comprise a plurality of integrated fastening elements. The mating housing components can be secured together by engaging integrated fastening elements, thereby securing the bits. The bits can thereby form a specified gap angle favorable for a blade-sharpening process. The integrated fastening elements can be of a snap fit cantilever beam design. Alignment posts can extend into and/or through the bits.

BACKGROUND

1. Field of the Invention

The present invention relates to hand-held knife sharpeners and moreparticularly to a device for sharpening cutlery, particularly cutleryhaving a blade that tapers to a thin edge.

2. Description of the Related Art

There are a variety of devices for sharpening cutlery, including:grinding wheels, sharpening stones, files, and specialized edgestripping devices for blades having a tapered edge. Strip sharpenerssuch as that disclosed in U.S. Pat. No. 4,624,157 “Pocket Sharpener forKnives” can operate longitudinally along the edge of a blade and cansimultaneously shave both sides of a tapered blade edge. Relative toother devices and methods, the use of a strip sharpener can provide aspecified optimum angle of taper to a blade edge. The requirements of astrip sharpening process allow for a compact tool design, and, forhand-held use.

Many extant strip-sharpening tool designs provide for fixedly securing apair of bits, thereby forming a specified gap angle. In some tools thebits are secured by screws engaged with a common supporting structurewhich can be a simple cylindrical rod. Screws can become loose overtime. In other tools the bits are fixedly secured within one or morehousing components and the housing components and/or bits themselvessecured together in a variety of ways. The housing components and/orbits are typically secured together by means of screws, rivets, and/oradhesives. In some cases, plastic housing components can be joined bysonic welds. Although such exemplary approaches to securing an assemblytogether can be effective, they also add cost and/or complication inmanufacturing. Such approaches require additional parts and/oradditional assembly operations and/or additional material and/or the useof specialized materials.

What is needed is a strip-sharpening tool that can be easily assembledfrom a relatively small number of parts, and with a minimum of assemblyoperations and/or other costs of manufacture.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts an embodiment of a blade-sharpening tool.

FIG. 2 depicts a sharpening process employing a blade-sharpening tool.

FIG. 3 depicts an embodiment of a blade-sharpening tool in an explodedaxonometric view.

FIGS. 4A, 4B, 4C depict an exemplary cantilever beam design for snap-fitconnection.

DETAILED DESCRIPTION

FIG. 1 illustrates an embodiment of a blade sharpening tool 100. Thetool comprises a first bit 101, a second bit 102, a first mating housingcomponent 103, and a second mating housing component 104. The bits 101102 can extend into and can be secured, within the assembly. In someembodiments, the bits 101, 102 can be fixed. In alternate embodiments,the bits can be pivotably, rotatably and/or rotatably coupled with thefirst and/or second mating housing components 103, 104. Each bit 101 102can be essentially box-shaped, that is, essentially a cuboid orrectangular prism. In some embodiments, the bits can be ovoid orelliptical and/or have any other known and/or convenient geometricproperties such that at a prescribed location the intersection of atleast two surfaces of the bits can form a predetermined gap angle 105.

A gap angle 105 can be specified, corresponding to a converging andoverlapping arrangement of the bits 101 102. The gap angle 105 is theangle between planes that essentially include the designated faces 107108. In some embodiments the gap angle can be specified as about 40degrees However, in alternate embodiments the bits 101 102 can begeometrically configured to form a gap angle 105 that can have anypredetermined angle or a variable angle based upon the geometry of theindividual bits 101 102.

FIG. 2 illustrates a sharpening process employing an embodiment of thetool 100. A tapered or to-be-tapered blade edge can be positionedagainst the bits 101 102 and drawn along the designated path 201 in theindicated direction. As the blade edge remains in contact with and movesacross the bits 101 102, blade material can be reshaped and/or removedby the action of the bits upon the blade. Blade material can be removedin strips due to this action, hence the designation of “strip sharpener”for such an embodiment.

The bits 101 102 can be fabricated of tungsten carbide material and/orother known and/or convenient material having properties suitable forsharpening a blade comprised of a known material. In some embodimentstungsten carbide bits, having a predetermined relative hardness, can beeffective in sharpening a variety of blades fabricated of steel and/orother materials and that span a prescribed range of relative hardnessesfrom 1-10 on the Mohs scale or an absolute hardness in any prescribedrange between 1 and 1500 on the absolute hardness scale.

In the orientation shown, a tool embodiment 100 can be conveniently heldand/or stabilized by an operator's left hand while the operator's righthand holds the knife or other cutlery and draws its blade along thedesignated path 201 in contact with the bits. The operator's left handcan be positioned at some distance from the blade and bits due to thelength of the tool, enhancing safety of operation. It can be appreciatedthat a simple inversion of tool position results in a convenientcomplementary orientation wherein an operator's left hand can similarlyhold and move the knife or other cutlery while the operator's right handholds and/or stabilizes the tool 100.

FIG. 3 is an exploded axonometric view of an embodiment of a bladesharpening tool 100. The tool comprises a first bit 101, a second bit102, a first mating housing component 103, and a second mating housingcomponent 104.

The first mating housing component 103 can comprise a plurality ofintegrated first fastening elements 301. The second mating housingcomponent 104 can comprise a plurality of integrated second fasteningelements 302. In assembly of the tool 100, the first and second matinghousing components 103 104 can be secured together by theinterengagement of the first fastening elements 301 with the secondfastening elements 302. The fastening elements can be of a snap-fit typedesign. In some embodiments the fastening elements can comprise membersof a cantilever beam snap-fit design. In an illustrated embodiment 100the first fastening elements 301 can be cantilever beam members, and thesecond fastening elements 302 can be cantilever beam-receiving members,of a snap-fit design. In alternate embodiments, the first housingcomponent 103 and the second housing component 104 can have any knownand or convenient shape and can be selectively coupled using any knownand/or convenient mechanism. In some embodiments, the housings 103 104can be configured such that the housing can be selectively coupled andde-coupled, such that one or more of the bits 101 102 can be replaced.However, in alternate embodiments, the housings can be configured suchthat once coupled they cannot be de-coupled without damage to one ormore of the housings 103 104.

In some embodiments the mating housing components 103 104 and/or otherintegrated design features can be fabricated of molded plastic and/orfabricated in an injection-molding process and/or fabricated ofhigh-impact polystyrene, and/or any other known and/or convenientmaterial

The first mating housing component 103 comprises a first channel 303,which can be integrally formed. A first bit-alignment post 305 isintegrated with a first mating housing component 103. The firstbit-alignment post 305 extends vertically as depicted in FIG. 3 from thefloor 307 of the first channel 303, along an axis essentially orthogonalto a horizontal plane essentially of that floor. In some embodiments thefirst bit-alignment post 305 can be of cylindrical shape. However, inalternate embodiments the alignment post 305 can have any known and/orconvenient geometric properties and/or in some configurations may not bepresent. The first channel 303 has a geometry sufficient to accept afirst bit 101. A first hole 309 in the first bit 101 has a geometrysufficient to accept the first bit-alignment post 305. The verticaldepth of the first channel 303 can be essentially equal to the verticaldepth of the first bit 101 as depicted in FIG. 3.

A complimentary second mating housing component 104 comprises a secondchannel 304, which can be integrally formed. A second bit-alignment post306 is integrated with a second mating housing component 104. The secondbit-alignment post 306 extends vertically as depicted in FIG. 3 from thefloor 308 of the second channel 304, along an axis essentiallyorthogonal to a horizontal plane essentially of that floor. In someembodiments the second bit-alignment post 306 can be of cylindricalshape. However, in alternate embodiments the alignment post 306 can haveany known and/or convenient geometric properties and/or in someconfigurations may not be present. The second channel 304 has a geometrysufficient to accept a second bit 102. A second hole 310 in the secondbit 102 has a geometry sufficient to accept the second bit-alignmentpost 306. The vertical depth of the second channel 304 can beessentially equal to the vertical extent of the second bit 102 asdepicted in FIG. 3. In some embodiments, the first channel 303 and/orsecond channel 304 can be comprised of one or more guide points, and/orany other convenient mechanism or mechanisms, located within the housing103 104 such that bit 101 and/or bit 102 are/is substantially restrainedfrom movement in at least one plane.

Each of the bits 101 102 can be essentially box-shaped, that is,essentially a cuboid or rectangular prism. Walls and/or otherrestraining mechanism bounding each channel 303 304 can constrainposition of the each of the respective bits 101 102 within a horizontalplane by closely surrounding some surfaces of the respective bits 101102 within that plane, as depicted in FIG. 3. Position of each bit 101102 in a horizontal plane can also be constrained by the respectiveinterlocking holes 309 310 and bit-alignment posts 305 306.

In alternative embodiments each bit-alignment post 305 306 can be ofalternative shape. In some embodiments, a horizontal cross-section of abit-alignment post 305 306 can comprise essentially a triangle,quadrilateral, or other polygon. The horizontal cross-section canalternatively comprise a closed shape comprising essentiallynon-polygonal features including by way of non-limiting example arcs. Anellipse is an example of a non-polygonal closed shape. A horizontalcross-section that is not circular can beneficially constrain rotationalposition of a bit 101 102 in a horizontal plane.

In some embodiments a first bit-alignment post 305 can be essentiallysquare in horizontal cross-section. A first hole 309 in the first bit101 can have a geometry sufficient to accept the square-aspectbit-alignment post. The accepting geometry can comprise a hole withsquare cross-section configured to engage the post 305. When assembledwith the first bit-alignment post 305 interlocked with the first hole309, rotation and translation of the bit in a horizontal plane can beconstrained by interference between the bit-alignment post 305 and thesurrounding hole 309.

In some embodiments one or both bit-alignment posts 305 306 can compriseextending edges that are essentially orthogonal to a horizontal planeessentially of a respective channel floor 307 308. In some embodiments,bit-alignment post shapes that are essentially right prisms can beemployed to facilitate manufacture. In some embodiments, tooling such asdrilling in order to form an accepting geometry of a bit-alignment post305 306 can be performed in an advantageous direction orthogonal to asurface of a bit 101 102.

In some embodiments of an assembled tool 100, the first bit 101 can beconstrained in position along a vertical axis as depicted in FIG. 3. Theposition of the first bit 101 can be constrained vertically by the floor307 of the first channel 303 and a surface of the second mating housingcomponent 104. In some embodiments of an assembled tool essentially zerovertical clearance remains after the vertical extent of the first bit101 between the surrounding channel floor 307 and the second matinghousing component 104.

Similarly, in some embodiments of an assembled tool 100, the second bit102 can be constrained in position along a vertical axis as depicted inFIG. 3. The position of the second bit 102 can be constrained verticallyby the floor 308 of the second channel 304 and a surface of the firstmating housing component 103. In some embodiments of an assembled toolessentially zero vertical clearance remains after the vertical extent ofthe second bit 102 between the surrounding channel floor 308 and thefirst mating housing component 103.

In some embodiments of an assembled tool 100, the first bit-alignmentpost 305 can extend from the floor 307 of the first channel 303 entirelyentirely through the first hole 309 of the first bit 101, and into athird hole 311 within the second mating housing component 104. The thirdhole 311 can have a geometry sufficient to accept the firstbit-alignment post 305.

Similarly, in some embodiments of an assembled tool 100, the secondbit-alignment post 306 can extend from the floor 308 of the secondchannel 304 through the second hole 310 of the second bit 102 and into afourth hole 312 within the first mating housing component 103. Thefourth hole 312 can have a geometry sufficient to accept the secondbit-alignment post 306.

In some embodiments a housing alignment post 315 can extend verticallyfrom the second mating housing component 104, as depicted in FIG. 3. Thehousing alignment post 315 can be integrally formed and/or otherwiseintegrated with the second mating housing component 104. In someembodiments a housing alignment post receiver 316 can be integrallyformed and/or otherwise integrated with the first mating housingcomponent 103. The housing alignment post receiver 316 can have ageometry sufficient to accept the housing alignment post 315. Duringassembly of the tool 100, the interlocking alignment post 315 andreceiver 316 can aid in guiding the mating housing components togetherby constraining relative (planar) translation of the first and secondmating housing components 103 104. The interlocking structure of post315 and receiver 316 can also aid in maintaining beneficial relativepositions of the mating housing components 103 104 in an assembled tool100.

FIGS. 4A 4B 4C illustrate an exemplary cantilever design for a snap-fitconnection, in cross-section. By way of example and not limitation, sucha design can be used in embodiments of the integrated fastening elements301 302. A cantilever beam design can have a cantilever beam member 401and a cantilever beam-receiving member 402. FIG. 4A depicts beam 401 andbeam-receiving member 402 prior to assembly. FIG. 4B depicts beam 401undergoing deformation as it travels into assembled position. FIG. 4Cdepicts beam 401 and beam-receiving member 402 in assembled position.

In an assembly process, the cantilever beam member 401 can undergoelastic and/or elasto-plastic deformations as the cantilever beam member401 and receiving member 402 are forced together into an assembledposition. In some embodiments, a cantilever beam and/or other members ofa design may return to an essentially undeformed state uponinterengaging assembly. In some embodiments, assembled members mayremain in a deformed state and thereby provide forces advantageous tothe function and/or performance of an assembled tool. By way of exampleand not limitation, a tool assembly wherein members are held in non-zerotension and/or compression resulting from deformation may thereby haveadvantageous reduction in vibration and/or relative movement of membersand/or other components of the assembled tool, when the tool is used.

It can be appreciated that in some embodiments during assembly and/orthereafter the cantilever beam-receiving member and/or other associatedcomponents of a tool can also undergo deformations. These deformationscan occur in combination with deformation of the cantilever beam. Suchdeformations can be considered in design.

For components of a tool that incorporates snap-fit-assembledcomponents, many considerations can contribute to selection and/orspecification of dimensions and/or materials and/or assembly and/ormanufacturing processes. In the present apparatus, any known and/orconvenient mechanism can be employed.

The outer perimeter of each mating housing component can comprise anedge of each housing that remains essentially exposed in an assembledtool 100. In cross-sections 313 314 as depicted in FIG. 3, each outerperimeter can comprise a right angle. In some alternative embodiments,one or both of the outer perimeters can comprise an alternative shape incross-section. By way of non-limiting examples alternative shapes caninclude bevels, arcs and/or any known and/or convenient geometry.

In addition to securing by interengagement of the integrated fastenerelements 301 302, in some embodiments of the assembled blade-sharpeningtool 100 the mating housing components 103 104 and/or bits 101 102and/or any other parts of the tool can be further secured together byadditional means. In some embodiments, these additional means cancomprise screws, rivets, adhesives, bands, clamps, sonic welds and/orany other known and/or convenient means of securing an assembly. In someembodiments the interengagment of the housings 103 104 can fixedlysecure the housings and/or the bits 101 102 relative to one another. Inalternate embodiments, the interengagement of the housing 103 104 canrestrict one or more degrees of freedom of the bits 101 102.

In some embodiments typical outer dimensions of an assembledblade-sharpening tool can be approximately 2.9 inches by approximately0.75 inches by approximately 0.28 inches. In some embodiments typicalouter dimensions of bits can be approximately 0.50 inches byapproximately 0.25 inches by approximately 0.63 inches. In someembodiments typical dimensions of each of the mating housing components103 104 can include a typical wall thickness of 0.075 inches. However,in alternate embodiment the blade-sharpening tool can have anyconvenient dimensions and/or geometric properties.

In the foregoing specification, the embodiments have been described withreference to specific elements thereof. It will, however, be evidentthat various modifications and changes may be made thereto withoutdeparting from the broader spirit and scope of the embodiments. Thespecification and drawings are, accordingly, to be regarded in anillustrative rather than restrictive sense.

1. A blade sharpening tool comprising: a first and a second matinghousing component; a first and a second bit; a plurality of firstfastening elements integrated with the first mating housing component; aplurality of second fastening elements integrated with the second matinghousing component; wherein the first and second mating housingcomponents are secured together by engagement of the plurality of firstfastening elements with the plurality of second fastening elements,thereby securing the first and second bits.
 2. An apparatus according toclaim 1 further comprising: a first channel in the first mating housingcomponent; a second channel in the second mating housing component; afirst bit-alignment post integrated with the first mating housingcomponent and located within the first channel; a second bit-alignmentpost integrated with the second mating housing component and locatedwithin the second channel; wherein a first hole extends into the firstbit, the first hole having a first geometry sufficient to accept thefirst bit-alignment post; wherein a second hole extends into the secondbit, the second hole having a second geometry sufficient to accept thesecond bit-alignment post; and wherein the first bit is locatedconstrained within the first channel and the second bit is locatedconstrained within the second channel, the bits thereby forming aspecified gap angle.
 3. An apparatus according to claim 1 wherein thefirst and second bits are of tungsten carbide material.
 4. An apparatusaccording to claim 1 wherein a first fastening element of the firstplurality of fastening elements and a second fastening element of thesecond plurality of fastening elements are of a cantilever beam design,and are interengaged.
 5. An apparatus according to claim 2 wherein thefirst and second bits are of tungsten carbide material.
 6. An apparatusaccording to claim 2 wherein a first fastening element of the firstplurality of fastening elements and a second fastening element of thesecond plurality of fastening elements are of a cantilever beam design,and are interengaged.
 7. An apparatus according to claim 2 wherein: thefirst hole extends through the first bit; and a third hole extends intothe second mating housing component, the third hole having a thirdgeometry sufficient to accept the first bit-alignment post.